Only child syndrome is a real thing according to scientific evidence — but it might not be what you think

Siblings are the longest relationships humans will ever have.Unsplash / Ben WhiteChildren who were born in China after the one-child policy was introduced in 1979 are known as "Little Emperors."

They're a generation who have been labelled as selfish, spoilt, and maladjusted because they had no siblings to rival or share with.

Around 30 years later, scientific research showed that this label probably wasn't just a myth. A lack of brothers or sisters appeared to make the only-children — now in their 20s and 30s — more self-centred, less co-operative, and less likely to get along with their peers.

These are the things only children — like me — are often accused of. We're told we never learned to share, and were spoilt by our parents because we were the centre of attention.

According to Avidan Milevsky, a research scientist of sibling relationships at Ariel University in Israel, there is extensive literature to show there really is such a thing as only child syndrome, particularly in terms of learning lessons that are important in adulthood.

"Our siblings offer so much to us throughout life, particularly when we're very young," Milevsky told Business Insider. "The way I learned about very important life social lessons is through my sibling relationships."

For example, children with siblings are taught about ownership very early on, such as when they try and take their little brother's truck, but are told it doesn't belong to them. Or how they learn to take turns, by slowing down and being patient until their sister or brother finishes doing whatever they're doing.

"The literature would suggest there is something about [only children] because they were lacking these important social relationships or learning these tasks early in life, meaning maybe they are more selfish or have difficulty with social interaction, sharing, or understanding social cues," Milevsky said.

There are ways to combat this, Milevsky says, because being an only child doesn't mean your fate is sealed. If your parents socialise you with playmates and have you surrounded by extended family — such as your cousins — from a young age, you can compensate for this lack of close relationships.

Not having a sibling can affect the structure of our brains.

A study last year by the Southwest University in Chongqing, China, examined the brain scans of 250 university students, half of which were only children. Their personalities were also tested for creativity and intelligence.

The researchers found that only children were more creative overall, but scored lower on having an agreeable personality.

The brain scans showed that this was at least partly down to the difference in the childrens' brain structures. Those who had higher creativity scores had a higher volume of grey matter in the parietal lobe — which is the part of the brain associated with our imaginations.

Only children who showed less agreeable personality traits had less grey matter in the medial pre-frontal cortex, which is the part that determines empathy, as its where we think about ourselves in relation to others.

The research team concluded that growing up with or without siblings can in fact adjust the structure of our brains.

Siblings provide a support network.

As an only child, I do sometimes think about what will happen when I have to experience major life events — from births to deaths — without a sibling. It seems that only child syndrome isn't just about how you yourself are altered, but also how you'll deal with the things everyone goes through.

Milevsky said that a sibling relationship is the longest one humans are likely to ever have. You will know your parents as long as they are around, but siblings can often be with each other for 80 years or more.

If your parents get divorced, as an only child you go through that experience alone. Those with siblings have someone to talk to, or at least they know someone who is going through the same thing.

Milevsky said he recently gave a lecture on this topic, and someone came up to him afterwards to describe how she found solace in her mother's passing away thanks to having several sisters.

"She described how comforting that was for her to have the sisters together as they mourned over the mother," he said. "That's something an only child is not going to have. It's a support network of like-minded people who are experiencing the same thing."